选择页面上具有特定类别的最后一个元素

我正在进行测验。我想选择页面上具有特定类的最后一个元素，以便当用户单击它时出现测验的结果。现在，我正在通过添加一个额外的类来做到这一点，但我想知道是否有一种无需使用类就可以遍历文档的方法，以便无论有多少个问题添加到测验中，该函数都会在最后一个触发时触发。单击元素。我尝试了这里和这里建议的解决方案，但似乎没有用。谢谢

我创建了以下codepen它

    //get total of questions
var $questionNumber = $('h2').length;
console.log($questionNumber);
//caching final score
var $totalScore=0;

$('li').click(function(){
    //caching variables
    var $parent = $(this).parent();
    var $span = $(this).find('.fa');

    //deactivate options on click
     $parent.find('li').off("click");

    //check for .correct class
        //if yes
        if($(this).hasClass('correct')){
            //add .correctAnswer class
            $(this).addClass('correctAnswer');
            //find next span and change icon
            $span.removeClass('fa fa-square-o').addClass('fa fa-check-square-o');
            //reduce opacity of siblings
            $(this).siblings().addClass('fade');
            //show answer
            var $answerReveal= $parent.next('.answerReveal').show();
            var $toShowCorrect = $answerReveal.find('.quizzAnswerC');
            var $toShowFalse = $answerReveal.find('.quizzAnswerF');
            $toShowCorrect.show();
            $toShowFalse.remove();
            //add 1 to total score
            $totalScore+=1;
            //console.log($totalScore);
        }else{
            //add .wrongAnswer class
            $(this).addClass('wrongAnswer').addClass('fade');
            //change icon
            $span.removeClass('fa fa-square-o').addClass('fa fa-check-square-o');
            //reduce opacity of its siblings
            $(this).siblings().addClass('fade');
            //show wrong Message
            var $answerReveal= $parent.next('.answerReveal').show();
            var $toShowCorrect = $answerReveal.find('.quizzAnswerC');
            var $toShowFalse = $answerReveal.find('.quizzAnswerF');
            $toShowCorrect.remove();
            $toShowFalse.show();
            //locate correct and highlight
            $parent.find('.correct').addClass('correctAnswer');
        };
});//end click function

//print Results
function printResult(){
    var resultText = '<p>';
    if ($totalScore === $questionNumber){
        resultText+='You got '+ $totalScore+ ' out of '+$questionNumber+'! </p>';
        $('.resultContainer').append(resultText);
        $('#halfText').append('<p>This is awesome!</p>');
        $('#halfImage').append('<img src="http://placehold.it/350x150" width="100%"><img>');
    }else if($totalScore>=3 && $totalScore < $questionNumber){
        resultText+='You got '+ $totalScore+ ' out of '+$questionNumber+'! </p>';
        $('.resultContainer').append(resultText);
        $('#halfText').append('<p>So and so...better luck next time</p>');
        $('#halfImage').append('<img src="http://placehold.it/350x150" width="100%"><img>');
    }else if ($totalScore<3){
        resultText+='You got '+ $totalScore+ ' out of '+$questionNumber+' </p>';
        $('.resultContainer').append(resultText);
        $('#halfText').append('<p>No..no...no...you have to try harder</p>');
        $('#halfImage').append('<img src="http://placehold.it/350x150" width="100%"><img>');
    }

};//end function

//final score
$('li.last').click(function(){
    //show result after last li is clicked
    var $height = $('.finalResult').height();
        printResult();
        console.log($totalScore)
        $('.finalResult').show();
        $('html, body').animate({ 
       scrollTop: $(document).height()-$height}, 
       1400);   
});